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According to the novel achievements, nanotopography and steric geometry of the microenvironment around the cells have a drastic role on their fates. Hence, fabrication of biocompatible nanostructures as the scaffolds for the cell culture and in the next step, accurate determination of their physical and geometrical characteristics is widely considered. Despite of broad utilization of Atomic Force Microscopy to investigate topological traits of sophisticated nanopatterns; its capability to characterize electrospun nanofibers has not been studied inquiringly. In the present research, chitosan nanofibers which were successfully electrospun at the optimized conditions were then evaluated using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) respectively. The results suggested that recruitment of both of these techniques have their own advantages and disadvantages. As the first noticeable issue, while the sample preparation and scanning procedure in SEM imaging may disrupt native structure of fibers, probing the sample by AFM doesn't need any pre-imaging treatment. The main application of SEM in analysis of nanofibrillar structures is the rapid survey of nanofibers shape, orientation, diameter and consistency. In the other side, three dimensional imaging by AFM makes it possible to determine whole surface roughness, roughness along fibers and woven tissue thickness. Furthermore, regarding some technical advices, AFM can be used to estimate nanofibers average diameter as well as SEM.

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 Graphene-based nanomaterials are being investigated for their biocompatibility and bioactivity, as well as their ability to improve osteogenic differentiation. In this research, the base material, reduced graphene oxide (rGO) sheets, were decorated with hydroxyapatite and strontium (rGO / HAp-Sr) to induce osteogenic differentiation in adipose-derived mesenchymal stem cells. Different techniques were used to determine the properties of the nanocomposite such as diffraction analysis techniques (XRD) and transmission electron microscopy (to evaluate the size and morphology of HAp-Sr on rGO plates), FT-IR (to analyze the nanocomposite functional group), Raman spectroscopy (to investigate possible disorders in nanocomposite structure and number of layers), induced dual plasma emission spectroscopy (to assess atomic concentration of Ca and Sr), zeta potential(electrical potential of the nanocomposite) and MTT (nanocomposite cytotoxicity assessment) were used. The ossification potential of the synthesized nanocomposite was investigated and confirmed using the calcium deposition test in dipose-derived mesenchymal stem cells. According to the obtained results, osteogenic differentiation induction is possible using synthesized nanocomposites without the need for chemical inducers.